BEIJING — China said Thursday that it will stick by its "freeze-for-freeze" proposal to de-escalate tensions on the Korean Peninsula, contradicting a suggestion by President Trump that it had turned against the plan.

The proposal calls for North Korea to freeze its missile and nuclear tests in return for the United States and South Korea suspending their annual joint military exercises. On Wednesday, Trump suggested Chinese President Xi Jinping had acknowledged to him that the plan was a non-starter.

But a spokesman for China's Foreign Ministry said that Beijing insisted that dialogue was the only solution, and that its proposal was still on the table.

"Suspension-for-suspension is the most realistic, viable and reasonable solution in the current situation," Geng Shuang said at a regular news conference. "I stress that it's only the first step, not the end."

And on Thursday, White House press secretary Sarah Huckabee Sanders acknowledged that the two leaders had not agreed that the freeze proposal should be dropped. She suggested that Trump and Xi had agreed to disagree on the matter, effectively tabling it.

"Yeah, both sides made their position clear," Sanders said when asked about Trump's assertion and the Chinese government's response. "They're different. But we agree that they're going to be different positions, and therefore it's not going to move forward."

The back-and-forth, coming just two days after the president's return from his Asia trip, highlights the lack of coherent policy put forward by the United States to actually usher North Korea along the path of denuclearization.

James Acton, co-director of the nuclear policy program at the Carnegie Endowment for International Peace, said the Trump administration deserves credit for raising the profile and urgency of the issue, and for pushing China to impose stricter sanctions than in the past.

But he said there was a lack of unity and clarity coming from the U.S. administration itself, over what actions from North Korea might open the door to negotiations, what an acceptable path was to de-escalation, and even whether its ultimate goal was still regime change.

"One question is what would the preconditions be for the U.S. to sit down with North Korea to negotiate," he said. "We've had at least three different answers to that question in the past week or two."

Yanmei Xie, an expert on China and North Korea at Gavekal Dragonomics, said China's announcement Wednesday that it is sending a special envoy to Pyongyang to brief the North Korean leadership "appears to give the lie" to Trump's assertion that he had convinced Xi to press Pyongyang to give up its nuclear weapons.

On Wednesday, Trump said at a briefing: "President Xi recognizes that a nuclear North Korea is a grave threat to China, and we agreed that we would not accept a so-called freeze-for-freeze agreement like those that have consistently failed in the past."

China's proposal has been rejected by Washington for a number of reasons, experts said: partly because it would undermine South Korea's defenses at a time when the threat is higher than ever and potentially spook a key ally, partly because a similar idea was tried in the early 1990s and failed, and partly because it implies some kind of moral equivalence between the actions of the United States and those of North Korea.

The proposal also lets China off the hook and plays into its attempts to portray the issue as solely a problem between headstrong governments in Washington and Pyongyang.

Experts say the risks of backtracking are also asymmetrical: The United States might cancel its annual military exercises, but if North Korea reneged on its side of the deal in subsequent weeks or months, those exercises would be very hard to reschedule.

China is the main economic backer of the North Korean regime, accounting for more than 80 percent of its official foreign trade.

It says it is strictly implementing sanctions agreed upon by the U.N. Security Council, but experts say it is unwilling to go further, refusing to take action that might destabilize or bring down the North Korean regime, or simply turn a nuclear-armed Pyongyang into an enemy of Beijing.

In his comments Wednesday, Trump also claimed that his Asia trip had forged new unity over the issue of North Korea's denuclearization, and said Xi had agreed "to use his great economic influence over the regime to achieve our common goal of a denuclearized Korean Peninsula."

But his comments made while in Asia lacked consistency.

In Seoul, Trump told the North Koreans that the path to a better future begins with "a stop to your development of ballistic missiles, and complete, verifiable and total denuclearization."

In Tokyo, he said that if North Korea returned Japanese citizens whom it had abducted, that could be a "tremendous signal" and would be the start of something.

The U.S. envoy to North Korea, Joseph Yun, is reported to have proposed that if North Korea announced and carried out a halt to its nuclear and missile tests for 60 days, that would be a sign that the United States should restart a dialogue.

Nor does the United States appear to have a proposal to counter China's freeze-for-freeze idea to de-escalate tensions, Acton said. It is unrealistic, he said, to expect agreement on denuclearization in a first round of talks, so interim steps to build confidence are essential.

"If you accept that premise, then what kind of interim outcome are we going to accept where we give North Korea some form of sanctions relief in return for it doing something down that path of denuclearization?" he asked, adding that the United States does not appear to have an answer to that question.

"The whole purpose of sanctions is you lift them if the other side does what you want them to do," he added. "The U.S. is very good at imposing sanctions; it's not so good at knowing the circumstances under which it will lift them."

In Tokyo, Prime Minister Shinzo Abe's government said Thursday that it was not aware of any agreement made by China to back away from the freeze-for-freeze proposal.

However, the Japanese government has been discussing a "maximum pressure" approach with the governments of South Korea and China, said Yoshihide Suga, the chief cabinet secretary.

Suga, Abe's top aide, echoed Trump's assertion that his trip to Asia was a "tremendous success" and credited the good start the American president got in Japan.

"We believe that the U.S. handled the North Korean issue in the following visits to South Korea and China based on the accomplishments of the Japan-U. S. summit," Suga said. "So we believe the president's Asia trip was extremely fruitful."

On Wednesday, China announced that it was sending a special envoy to North Korea to brief Pyongyang on its recently concluded Communist Party congress, and to talk about other issues of mutual concern, reopening a channel of communication to the isolated regime.

But Xie, of Dragonomics, didn't see that as part of an effort to apply pressure on North Korea.

While in Asia, she said, Trump toned down his belligerent rhetoric and spoke in more measured tones about North Korea, pledging for example to use "all available tools short of military action."

"With unilateral U.S. military action off the table as too risky, and little or no prospect China will apply severe economic sanctions, the U.S. administration has little option but to accept that it will have to live with a nuclear North Korea," she wrote in a client note.

"For Washington that is hardly an ideal outcome, but on the positive side it means the tail risk of a war on the Korean Peninsula is receding."

Anne Gearan in Washington, Yuki Oda in Tokyo and Liu Yang and Amber Ziye Wang in Beijing contributed to this report.